build providers: idempotent destroy for LXD

[sergiusens]

Fixes SNAPCRAFT-MB

Signed-off-by: Sergio Schvezov sergio.schvezov@canonical.com

• Have you followed the guidelines for contributing?
• Have you signed the CLA?
• Have you successfully run ./runtests.sh static?
• Have you successfully run ./runtests.sh tests/unit?

---

Before

(snapcraft) multipass@lxd-snapcraft:~/t$ snapcraft --use-lxd
Using 'snap/snapcraft.yaml': Project assets will be searched for from the 'snap' directory.
The LXD provider is offered as a technology preview for early adopters.
The command line interface, container names or lifecycle handling may change in upcoming releases.
Launching a container.
Sorry, an error occurred in Snapcraft:
Traceback (most recent call last):
  File "/home/multipass/snapcraft/snapcraft/internal/build_providers/_base_provider.py", line 249, in launch_instance
    self._start()
  File "/home/multipass/snapcraft/snapcraft/internal/build_providers/_lxd/_lxd.py", line 166, in _start
    raise errors.ProviderInstanceNotFoundError(instance_name=self.instance_name)
snapcraft.internal.build_providers.errors.ProviderInstanceNotFoundError: Cannot find an instance named 'snapcraft-test'.

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/home/multipass/snapcraft/snapcraft/internal/build_providers/_lxd/_lxd.py", line 151, in _launch
    container = self._lxd_client.containers.create(config, wait=True)
  File "/home/multipass/venv/snapcraft/lib/python3.6/site-packages/pylxd/models/container.py", line 276, in create
    response = client.api.containers.post(json=config, target=target)
  File "/home/multipass/venv/snapcraft/lib/python3.6/site-packages/pylxd/client.py", line 168, in post
    self._assert_response(response, allowed_status_codes=(200, 201, 202))
  File "/home/multipass/venv/snapcraft/lib/python3.6/site-packages/pylxd/client.py", line 108, in _assert_response
    raise exceptions.LXDAPIException(response)
pylxd.exceptions.LXDAPIException: No storage pool found. Please create a new storage pool

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "/home/multipass/snapcraft/snapcraft/internal/build_providers/_base_provider.py", line 117, in __enter__
    self.create()
  File "/home/multipass/snapcraft/snapcraft/internal/build_providers/_lxd/_lxd.py", line 246, in create
    self.launch_instance()
  File "/home/multipass/snapcraft/snapcraft/internal/build_providers/_base_provider.py", line 257, in launch_instance
    self._launch()
  File "/home/multipass/snapcraft/snapcraft/internal/build_providers/_lxd/_lxd.py", line 155, in _launch
    ) from lxd_api_error
snapcraft.internal.build_providers.errors.ProviderLaunchError: An error occurred with the instance when trying to launch with 'LXD': No storage pool found. Please create a new storage pool.
Ensure that 'LXD' is setup correctly and try again.

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/home/multipass/venv/snapcraft/bin/snapcraft", line 11, in <module>
    load_entry_point('snapcraft', 'console_scripts', 'snapcraft')()
  File "/home/multipass/snapcraft/snapcraft/cli/__main__.py", line 81, in run
    run_snapcraft(prog_name="snapcraft")
  File "/home/multipass/venv/snapcraft/lib/python3.6/site-packages/click/core.py", line 722, in __call__
    return self.main(*args, **kwargs)
  File "/home/multipass/venv/snapcraft/lib/python3.6/site-packages/click/core.py", line 697, in main
    rv = self.invoke(ctx)
  File "/home/multipass/venv/snapcraft/lib/python3.6/site-packages/click/core.py", line 1043, in invoke
    return Command.invoke(self, ctx)
  File "/home/multipass/venv/snapcraft/lib/python3.6/site-packages/click/core.py", line 895, in invoke
    return ctx.invoke(self.callback, **ctx.params)
  File "/home/multipass/venv/snapcraft/lib/python3.6/site-packages/click/core.py", line 535, in invoke
    return callback(*args, **kwargs)
  File "/home/multipass/venv/snapcraft/lib/python3.6/site-packages/click/decorators.py", line 17, in new_func
    return f(get_current_context(), *args, **kwargs)
  File "/home/multipass/snapcraft/snapcraft/cli/_runner.py", line 93, in run
    ctx.forward(lifecyclecli.commands["snap"])
  File "/home/multipass/venv/snapcraft/lib/python3.6/site-packages/click/core.py", line 553, in forward
    return self.invoke(cmd, **kwargs)
  File "/home/multipass/venv/snapcraft/lib/python3.6/site-packages/click/core.py", line 535, in invoke
    return callback(*args, **kwargs)
  File "/home/multipass/snapcraft/snapcraft/cli/lifecycle.py", line 272, in snap
    _execute(steps.PRIME, parts=[], pack_project=True, output=output, **kwargs)
  File "/home/multipass/snapcraft/snapcraft/cli/lifecycle.py", line 98, in _execute
    with build_provider_class(project=project, echoer=echo) as instance:
  File "/home/multipass/snapcraft/snapcraft/internal/build_providers/_base_provider.py", line 120, in __enter__
    self.destroy()
  File "/home/multipass/snapcraft/snapcraft/internal/build_providers/_lxd/_lxd.py", line 250, in destroy
    self._stop()
  File "/home/multipass/snapcraft/snapcraft/internal/build_providers/_lxd/_lxd.py", line 196, in _stop
    self._container.sync()
AttributeError: 'NoneType' object has no attribute 'sync'
We would appreciate it if you created a bug report at
https://launchpad.net/snapcraft/+filebug with the above text included.

and after

(snapcraft) multipass@lxd-snapcraft:~/t$ snapcraft --use-lxd
Using 'snap/snapcraft.yaml': Project assets will be searched for from the 'snap' directory.
The LXD provider is offered as a technology preview for early adopters.
The command line interface, container names or lifecycle handling may change in upcoming releases.
Launching a container.
An error occurred with the instance when trying to launch with 'LXD': No storage pool found. Please create a new storage pool.
Ensure that 'LXD' is setup correctly and try again.

[codecov-io]

Codecov Report

Merging #2529 into master will decrease coverage by <.01%.
The diff coverage is 0%.

@@            Coverage Diff            @@
##           master   #2529      +/-   ##
=========================================
- Coverage    89.1%   89.1%   -0.01%     
=========================================
  Files         201     201              
  Lines       13650   13652       +2     
  Branches     2065    2066       +1     
=========================================
+ Hits        12163   12164       +1     
- Misses       1048    1050       +2     
+ Partials      439     438       -1

Impacted Files	Coverage Δ
snapcraft/internal/build_providers/_lxd/_lxd.py	23.39% <0%> (-0.28%)	⬇️
snapcraft/internal/elf.py	81.07% <0%> (+0.35%)	⬆️

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